It's seems that the url from the alert pop up is related to Azure code, Without support for Azure Code Signing, it will not be possible to install or upgrade to later product versions starting from a specific version/build number.


"Unfortunately it's not possible to install support for Azure code signing (Trusted signing): https://support.microsoft.com/en-us/topic/october-12-2021-kb5006669-os-build-14393-4704-expired-bcc95546-0768-49ae-bec9-240cc59df384


As of 9/12/2023, KB5006669 is no longer available from Windows Update, the Microsoft Update Catalog, or other release channels. -ESET HQ"

I asked them the below :


Thank , what is the best recommendation to them , they have to do an upgrade to the latest version of Windows Server 2016 DC VM’s. is that correct, to disappear the warning?


"Yes, updating to the most recent version of Windows Server 2016 DC VMs should resolve the issue. To avoid problems, make sure to adhere to best practices during the update process.-ESET HQ"


Source:  Operating system update necessary to install or upgrade ESET products